[NET]: Forget the zero_it argument of sk_alloc()

Finally, the zero_it argument can be completely removed from
the callers and from the function prototype.

Besides, fix the checkpatch.pl warnings about using the
assignments inside if-s.

This patch is rather big, and it is a part of the previous one.
I splitted it wishing to make the patches more readable. Hope 
this particular split helped.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index ecad7b4..20de3fa 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -779,7 +779,7 @@
 
 extern struct sock		*sk_alloc(struct net *net, int family,
 					  gfp_t priority,
-					  struct proto *prot, int zero_it);
+					  struct proto *prot);
 extern void			sk_free(struct sock *sk);
 extern struct sock		*sk_clone(const struct sock *sk,
 					  const gfp_t priority);